Grant: Research Tools and Instruments - Category 1 (<$150,000)

Humans depend on making actions for their survival. Most research in Psychology and Neuroscience has concentrated on actions made in response to imperative cues (i.e., reactions). This has led to a dearth of knowledge about how intentional actions are produced, in the absence of imperative cues. To clarify, an action can be made because an environmental signal cues it (e.g., a traffic light) or because an individual simply ""decides"" to act (i.e., intentional action). Many compulsive and impulse control disorders are accompanied by an inability to appropriately inhibit actions. I am seeking equipment that will enable us to elucidate some of the neurophysiological mechanisms through which intentional action emerges and is regulated. Specifically, by using paired pulses of Transcranial Magnetic Stimulation (TMS) it is possible to investigate inhibitory processing in the brain regions that mediate human action. We recently proposed a model of intentional action that has inhibitory processing as a core component and it is through the use of paired pulse TMS (requested in this application) that we wish to test our model. We are also requesting funds for purchase of a Transcranial Direct Current Stimulation system (tDCS). This system enables researchers to transiently disrupt processing in brain regions that are believed to be involved in the cancellation of intended actions. By transiently disrupting the right inferior frontal gyrus and the fronto-median cortex, and measuring participants' ability to ""stop"" an intentional action (using a behavioural paradigm we have previously developed), it will be possible to confirm the roles of these regions in the cancellation of intentional actions. Through our experiments, the hope is to gain insight into the mechanisms that govern the production and regulation of intentional actions. As well as advancing our fundamental knowledge about how the brain governs intended actions, our work could have future implications for individuals with abnormal regulation of intentional action.